The tactician, who replaced Liam Rosenior after his January departure to Chelsea, saw the Ligue 1 team’s campaign end without a European place after an eighth-place finish.
The club had briefly shifted focus late in the season towards cup success, but were eliminated from both the Coupe de France and the UEFA Conference League at the semi-final stage.
“We are very happy with his (O’Neil’s) work and he is very happy with Le Racing. Gary is involved, motivated, and has begun work on the squad for next season,” Keller told DNA Sports.
“His objective consists of increasing the rhythm and our levels of expectations because teams in the top eight (of Ligue 1) are moving quickly.”
Reports earlier this month suggested Strasbourg were considering potential replacements, including interest in Luis Felipe, but those doubts have now been put to rest.